The refuge sits on Florida's east coast near Titusville (Florida map) and is home to some 330 avian species.
To prevent bird-related problems with Discovery's current mission, Payne and his NASA teammates came up with several techniques to keep winged trespassers away.
Team members put several of their ideas to the test for the July 4 launch.
One such anti-vulture measure is decidedly low-tech.
Because the scavenger birds feed on roadkill, NASA trained staff who drive to and from the space center to take extra precautions to avoid hitting animals on the roads.
This "food-source reduction system, which we call our roadkill roundup has been very effective in terms of encouraging the vultures to seek food elsewhere," Payne said.
Vultures in particular are a major threat to the shuttle, because they tend to soar, Payne says.
The birds gain altitude using the warm updrafts that radiate from structures around the launch pad. They fly high enough, the NASA team says, to pose a potentially serious risk to an accelerating orbiter.
"Most of the smaller birds we have [at the space center] don't fly as high, and they don't linger around the pads," Payne said.
NASA also tried luring vultures away from the launch pad by strategically positioning bait-and-release cages at other points around the space center.
"We've seen a general decrease in the [local vulture] population and a decrease around the pad," Payne said.
To keep track of remaining birds' locations, he and his colleagues installed a radar and camera system near the launch pad.
The equipment was originally designed for tracking birds at airfields.
"It's very sensitive," Payne said. "It can identify individual birds."
If a few birds approach the pad during a countdown, the camera system "gives us an awareness of where they are before we shoot the rocket," he added.
The NASA team intends to implement other possible solutions before planned launches later this year.
Acid Rain, Natural Darkness
Dorn Whitmore of the U.S. Fish and Wildlife Service says he was surprised when the shuttle hit a vulture last year.
"There's so much activity around those launch pads before the launch that I think that birds sense that and move away from the area," said Whitmore, who is chief ranger of the Merritt Island refuge.
NASA consulted the refuge while devising its solution to the latest avian danger, as they did previously when other wildlife-related concerns arose, Whitmore says.
In the 1980s, for example, NASA changed a boat-propulsion system to avoid injuring manatees while retrieving shuttles' spent external tanks from the sea.
"They've been a very good partner over the years," he said of the space agency.
Launches do have additional environmental impacts, Whitmore notes.
"We get acid rain that falls out of [the exhaust] cloud right after launch," he said. Particles in the exhaust are absorbed into water droplets, making the rain more acidic than normal.
"If a raindrop hits a plant, it leaves a spot on the leaf," Whitmore said. Fortunately, the refuge's alkaline soil counteracts the acid, minimizing its harm, he adds.
Of course, Whitmore says, the space center's presence led to the creation of the refuge around it, which has kept urban development and its ecological hazards at bay.
Light pollution from urban areas discourages sea turtles from nesting along other stretches of Florida's shore. But the beaches within the refuge around the Kennedy Space Center is an oasis of darkness at night.
The sea turtles need a secluded, darker locale for laying their eggs (read "Saving Sea Turtles With a Lights-Out Policy in Florida").
"Dark natural beaches are a premium on Florida's coastline today," he said. "Right in the shadow of the shuttle, sea turtles will come up and nest at night."
"Inadvertently," he said, "NASA has protected a very important area."
NASA's Payne added, "We're making every effort not to injure any birds. We're trying to gently discourage them from being here."
Jenny Pegg contributed reporting for this article.
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